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L: WSTOGKWELL. SCREW THREADING MACHINE. No. 259,483. v Paten td June 13, 1882,

7/ 5M W QM @o s Q ORQk-W UNITED STATES Y FFICE.

E ATENT LEVI WV. STOGKWELL, OF CLEVELAND, OHIO, ASSIGNOR TO WILLIAM H. PRICE, OF SAME PLACE.

SCREW-TH READING MACHINE.

SPECIFICATION forming part of Letters Patent No. 259,433, dated June 13, 1882.

' Application filed October 9, 1879.

To all whom it may concern:

Be it known that I, LEVI W. STOCKWELL, of Cleveland, Ohio, have invented a new and useful Improvement in Screw-Threading Machines, of which the followingis a specification.

The nature and object of my invention is a screw-threading machine in which the scroll that holds and adjusts the threading-dies in the cutter-head is turned to open and close the dies by means of a sliding collar having a pin which enters a cam-slot in a ring attached to the scroll.

Figure 1 is an elevation. Fig. 2 is a horizontal section. Fig. 3 represents the scrollring.

The cutter-head or stock a carries threadingdies 1), which are held and moved toward and from the axis of the cutter-head by concentric cams 0 on scroll-ring c entering slots in the dies. The cutter-head a has a flange, b, at the end of its shank,through which itmaybe bolted to the face-plate of a lathe or any rotating wheel to operate the machine. The ring a is attached by bolts 6 e to scroll-ring c, and has a flange extending backward over a part of sliding collar 0?. It has a cam-slot, c diagonal to the axis of the cutter-head, except at the closed end of the slot nearest to scroll-ring c, where the sides of the slot are parallel with the axis of the cutter-head. By sliding forward collar a on the shank of the cutter-head its pin f in cam-slot 0 turns ring a and scroll c on the cutter-head a, and thereby causes the concentric cams c to close the threadingdies. By sliding back collar a the motion of ring a and scroll 0 on the cutter-head is reversed and the dies opened. When the dies are closed and cutting-threads, scroll c, and ring a are prevented from turning on the cutter-head by the sides of slot 0 which are then in contact with pin f, being parallel with the axis of the cutter-head.

Sliding collar a is feathered to the shank of cutter-head a, and is operated by the jointed lever h, pivoted to loose rings d d. Sliding collar c rotates in ring d, which is in an annular groove in collar a and the shank of cutter-head a rotates in ring d.

Cam-slot may be made in collar a and pin f placed in ring a, if preferred.

Scroll c has two circular slots, on w, to receive bolt e and its head. Bolts 0 c extend through slots 00 m and ring a, and are for the purpose of firmly attaching scroll c and ring a to gether, which is done by turning threaded nuts n n on the bolts. When nuts 02 n have been loosened on bolts e e scroll a may be turned without turning ring a for the purpose of adjusting the dies 1). The circular slots :0 so are of a length to permit scroll c to be thus turned sufficiently to move the whole length of cams 0 through the slots in the dies. There is a space between the ends of adjacent cams 0 equal to the width of die I). When scroll c has been turned, as above stated, on cutter-head to until cams c and the die-slots in the cutter-head are in the relative positions shown in Fig. 3, the dies b become dislodged from cams c, and may be removed and replaced. In replacing the dies in the cutter-head a pin 8 in the side of each die comes in contact with the side of cam c at the outer end of the cam, and arrests the die in position for the cam to enter the slot in, the die by turning scroll c on the cutter-head. Scroll 0 is thus turned by handle it, inserted in a hole in the circumference of the scroll. There is a small slot, 8, in cutter-head a, at the side of the die slot, for pin 8 to enter.

Machines have heretofore been madein which the scroll actuating the dies has been turned by means of spiral projections on a sliding sleeve, and in expansion-taps a sleeve havinga rotary motion has been given a sliding motion by means of a cam-slot somewhat similar in form to the one herein described, but in a different relative position to the axis of the spin dle, for the purpose of arresting the sliding motion of the sleeve and dies in a direction lengthwise of the spindle.

I claim as my invention-- The cutter-head a, provided with scroll 0, having a rotary motion to open and close the dies, and ring a, formed with a cam-slot, c, a part of which is parallel with the axis of the cutter-head for the purpose of arresting the rotary motion of the scroll, in combination with the sliding collar 44 having pin f, substantially as described.

LEVI W. STOOKWELL.

Witnesses:

J AS. H. OADY, WM. H. HAWKINS. 

